1. Technical Field
The present invention relates to a light irradiation device, and a printing apparatus provided with the light irradiation device.
2. Related Art
A printing apparatus (for example, an ink-jet printer) according to related art applies photo-curable ink (for example, ultraviolet-ray curable ink) onto a medium to form a print image, and, after that, irradiates the print image with light (for example, ultraviolet rays) by means of a light irradiation device for image fixation (the curing of the applied photo-curable ink). In such a printing apparatus, if the amount of light irradiation to photo-curable ink is insufficient, a print image is not fixed sufficiently. Therefore, it is necessary that a light irradiation device should be configured to irradiate, with light uniformly and sufficiently, the entire surface of a medium onto which photo-curable ink has been applied. In addition, it is necessary to maintain such a uniform and sufficient irradiation state. In connection with this, a technique (illumination device) that can make the distribution of illuminance uniform by arranging light emission elements classified into different levels of luminous intensity (irradiation intensity) on the basis of a predetermined arrangement rule is disclosed in JP-A-2008-180842.
However, in the illumination device disclosed in JP-A-2008-180842, if the difference in luminous intensity (irradiation intensity) among the classified light emission elements is excessively large, a problem of the lack of uniformity in irradiation occurs even if the light emission elements are arranged on the basis of a predetermined rule. That is, in order to avoid this problem, it is necessary that the illumination device should be made up of groups of light emission elements whose difference in luminous intensity (irradiation intensity) falls within a predetermined range. For this reason, for example, in some cases, variations among the manufacturing lots of light emission elements are not tolerable.